The invention relates to a magnetic-tape-cassette apparatus comprising a deck for magnetic-tape cassettes, which deck is constructed for playing and fast-winding operation with a first and an opposite second tape-transport direction, for which purpose it comprises, in addition to a first and a second selectively drivable reel disc for the magnetic tape, a first and a second capstan adapted to be driven in different directions of rotation by a motor, and which magnetic-tape-cassette apparatus comprises a switching mechanism comprising a movable transport member by means of which the reel-disc drive can be switched from one reel disc to the other reel disc in order to change the tape-transport direction, the transport member having axially spaced toothed-rack portions.
DE-OS 38 36 246 describes a switching mechanism with a transport member having toothed-rack portions at both ends in the direction of longitudinal movement. The longitudinal movement of the transport member causes toothed segments to be moved, via which toothed segments pressure rollers associated with the capstans can alternately be lifted off or applied to the capstans or can both be lifted off the capstans. The transport member is actuated via a lever system which changes over when the direction of rotation of the drive motor changes.
It is an object of the invention to provide a magnetic-tape-cassette apparatus comprising a deck of the type defined in the opening paragraph, in which during the movement of the transport member the transport member switches the drive from one reel disc to the other in the case that a drive motor having only one direction of rotation is used.
According to the invention this object is achieved in that for moving the transport member the toothed-rack portions selectively cooperate with oppositely rotating toothed drive wheels, and the transport member is arranged to be pivotable transversely of its direction of translation in such a way that the meshing between a toothed-rack portion and a drive wheel is cancelled in the final stage of the translation movement by a tilting movement of the transport member to disengage the teeth, said tilting movement and the return into a neutral center position being obtained by means of a return spring which is pretensioned during the transverse movement.
After a specific travel the transport member is thus disengaged from the moving teeth by means of the return spring and is returned into its neutral center position by means of the same return spring. This construction is very compact and reduces the number of parts.
In a further embodiment of the invention the return spring has a spring limb which, as it is pretensioned, presses against a pressure pin of the transport member in the tilting direction for disengagement, another spring limb being pretensioned in the return direction by means of a coupling element of the transport member. Thus, one of the operating functions, such as tilting and returning to the neutral center position, is assigned to each of the legs of the return spring itself.
In a further embodiment of the invention at its axial end portions the transport member has guide-pin grooves and tilting grooves which extend parallel to the longitudinal axis of said transport member and pairwise adjacent to one another and which are interconnected in such a way that a guide pin, which has entered a guide-pin groove during the transverse movement, changes over from the guide-pin groove into the tilting groove in the tilting range, the transport member being tilted to cancel meshing of the teeth both under the influence of the disengaging forces of the teeth and under the influence of the force of the return spring. A transport member of such a configuration can be injection-moulded without any problems The translational movements are performed by the toothed drive wheels, the pivotal movement both as regards its timing and spatial relationship being realised by means of the return spring
In a further embodiment of the invention the return spring is constructed as a hairpin spring between whose limbs, viewed from the hairpin bend, an actuating pin and, spaced therefrom, a transport-member coupling element are situated Such a hairpin spring can be used very advantageously for both movement functions, i.e. the pivotal movement and the return to the neutral center position.
In a further embodiment of the invention the transport member carries a stop which cooperates with guide members which are fixedly connected to the apparatus, in such a manner that the stop brakes the return movement of the transport member by abutment against the guide members before said transport member reaches its neutral center position, as a result of which the return spring has a tilting effect on the transport member and tilts said member back into its non-tilted normal position, in which the stop has no effect and the transport member can be moved into and latched in its neutral center position.